The need for new tests, protocols and models to identify people with significant exposures to environmental toxins and to assist clinicians to recognise and respond to subtle, early affects before they progress to debilitating, chronic disease are our long term goals. The objective of this application is to assess the affect of specific environmental toxins or combination of toxins on the immune system. The central hypothesis to be tested is specific environmental toxins effect leukocyte function and genotype in relation to amount of toxin, time of exposure and immune status prior to exposure. An understanding of this relationship is important for health risk assessment. This research is needed to reduce uncertainties in current environmental risk estimates and to develop improved risk assessment models. The specific aims will includc (1) evaluation of the genotoxic affect of environmental toxins using a new, cost effective method of quantifying DNA by the coefficient of variance index and (2) evaluation of immune cell function using activation/proliferation, oxidative burst, Calcium flux and phagocytosis assays. Three populations of specimens will be assessed: (1) human leukocytes from preexisting diagnostic samples, (2) leukocytes from healthy mice; the cells will be exposed to various amounts toxins and various exposure times; (3) leukocytes from the murine AIDS model will also be exposed to various amounts of toxins and various exposure times.